Williamson County, Illinois
Lat/Long: 37.7333, -88.9333
The Illinois General Assembly created Williamson County in 1839 out of Franklin County. Later that year, commissioners appointed for the purpose located the county seat at a site near the center of the new county and named it Marion.
An Act to Establish the County of Williamson; History of Gallatin, Saline, Hamilton, Franklin and Williamson Counties, Illinois (Chicago: Goodspeed, 1887), 450-52.